ABSTRACT The growth and importance of the Brazilian citrus industry in the world involves the introduction of technologies such as the use of plant growth regulators such as gibberellic acid (GA3). The effects of doses of 0, 5, 10 and 15 mg L-1 of GA3 (Pro-Gibb®) associated with the surfactant Silwett L-77® at 0.5 mL L-1 were evaluated in an experiment by spraying the plants of a ‘Natal’ orange orchard in the Northern region of the state of São Paulo, Brazil. The treatments were applied annually, for two years, when the fruits were still fully green, but before the flowering of the next crop. The results showed, at the picking period, that the treatment of ‘Natal’ sweet orange trees with gibberellic acid associated with silicone surfactant, reduced fruit abscission due to the higher force needed to detach the fruits from the plants and significantly increased the peel resistance to puncture; The maintenance of the greener color of the orange peel, evaluated using a colorimeter, make them less attractive to fruit flies and make it possible the delay on insecticides treatments for flies control. Additionally, it allows the delay on harvesting by storing the fruits on the plants, with staggered harvest beyond the normal period for the variety. It is suggested doses of 5 to 10 mg L-1 GA3 always associated to silicone surfactant (0.05% L77) to obtain the best responses in oranges of Natal cultivar. Treatments with GA3 did not affect the productivity of the ‘Natal’ sweet orange orchard, neither the maturation and nor the technological quality of the fruits.

RESUMO O crescimento e importância da citricultura brasileira no mundo passa pela introdução de tecnologias como a utilização de reguladores vegetais como o ácido giberélico (GA3). Os efeitos das doses de 0, 5, 10 e 15 mg L-1 de GA3 (Pro-Gibb®) associado ao surfactante Silwett L-77® a 0,5 mL L-1 foram avaliadas em experimento pulverizando as plantas de um pomar de laranjeira ‘Natal’ na região Norte do estado de São Paulo, Brasil. A aplicação dos tratamentos deu-se anualmente, durante dois anos, quando os frutos ainda estavam totalmente verdes, porém antes do florescimento da próxima safra. Os resultados mostraram por ocasião da colheita que o tratamento das laranjeiras ‘Natal’ com ácido giberélico associado a surfactante siliconado, diminuiu a abscisão de frutos pela maior força necessária para destacar os frutos das plantas durante a colheita e aumentou significativamente a resistência da casca à punctura. A manutenção da coloração mais esverdeada da casca dos frutos, avaliada através de colorímetro, os tornam menos atrativo às moscas das frutas e assim possibilita retardar as aplicações de inseticidas para controle das moscas. Além disso, permite retardar as colheitas armazenando os frutos nas plantas, com colheitas escalonadas para além do período normal para a variedade. Sugere-se doses de 5 a 10 mg L-1 GA3 sempre associado a surfactante siliconado (0,05% L77) para se obter as melhores respostas em laranjas da variedade Natal. Os tratamentos com GA3 não afetaram a produtividade do pomar de laranja ‘Natal’, nem a maturação e nem a qualidade tecnológica dos frutos.

Resumen El objetivo de este estudio fue evaluar el rendimiento deshuesado en canal de 64 toros jóvenes Nellore alimentados en corral con dietas que contienen urea recubierta o sin recubrir y sacrificados a cinco pesos corporales (350, 455, 485, 555 y 580 kg). Se utilizó un diseño completamente aleatorizado con un arreglo factorial de 5 χ 2. No se detectó ningún efecto significativo para la interacción entre el peso de sacrificio y la dieta; por lo tanto, las variables se analizaron por separado, en comparación con los contrastes polinómicos y la prueba F, respectivamente. Los pesos absolutos de los cortes primarios del cuarto anterior y posterior aumentaron linealmente a medida que aumentaba el peso del sacrificio de los animales. El aumento de los pesos de sacrificio elevó el porcentaje de la tapa de la grupa en el cuarto trasero de la pistola, así como su rendimiento. Los porcentajes de la gorguera y la falda de la rabadilla aumentaron linealmente, mientras que los de nudillo, lomo, filete de flanco, grupa y plano exterior disminuyeron y la suma de los cortes primarios tuvo un efecto cuadrático en relación con el peso de la mitad de la carcasa. El aumento de los pesos de matanza condujo a un mayor porcentaje de grasa del recorte de los cortes del cuarto trasero en relación con el peso de la carcasa 1/2. El peso de los cortes de carne fue similar entre los grupos de animales alimentados con urea recubierta y no recubierta. Los pesos de sacrificio más altos generan cortes de carne más pesados pero porcentajes más bajos de cortes primarios del cuarto trasero de la pistola en relación con el peso de la carcasa.

Abstract The aim of this study was to evaluate the boneless yield of the carcass of 64 feedlot-finished young Nellore bulls fed diets containing coated or uncoated urea and slaughtered at five body weights (350, 455, 485, 555, and 580 kg). A completely randomized design with a 5 χ 2 factorial arrangement was used. No significant effect was detected for the interaction between slaughter weight and diet; therefore, the variables were analyzed separately, compared by polynomial contrasts and the F test, respectively. The absolute weights of the primal cuts from the fore- and hind-quarter increased linearly as the slaughter weight of the animals increased. Increasing slaughter weights elevated the percentage of rump cap in the pistola hindquarter as well as its yield. The percentages of the rump cap and rump skirt increased linearly, whereas those of knuckle, tenderloin, flank steak, rump, and outside flat decreased and the sum of prime cuts had a quadratic effect in relation to the weight of the right 1/2 carcass. Increasing slaughter weights led to a higher percentage of fat from the trimming of the hindquarter cuts relative to the weight of the 1/2 carcass. The weight of meat cuts was similar between the groups of animals fed coated and uncoated urea. Higher slaughter weights generate heavier meat cuts but lower percentages of primal cuts from the pistola hindquarter relative to the carcass weight.

This study analyzes the chemical carcass characteristics and carcass losses in 86 cattle, both castrated and non-castrated, with an average initial weight of 329 kg and an average age of approximately 20 months, including 12 Gyr, 20 Guzerat, 20 Nellore, and 20 Caracu among the herds selected for weight determination at 378 days of age, as well as 14 Nellore cattle that were not selected. The diet contained a roughage-to-concentrate ratio of 60:40 in terms of dry matter (DM), with 14.8% crude protein as a percentage of DM and corn silage as roughage. A completely randomized 5 × 2 factorial experimental design was used, including five breeds and two sex classes. The following values were determined: losses due to the trimming of commercial cuts and cooking; shear force; the temperature and pH of the meat; and the chemical composition of the Hankins and Howe section (HH section). The castrated animals exhibited greater losses from the front trimmings compared with the non-castrated cattle. There were no differences in the final pH values of the carcasses among the breeds, although the noncastrated animals exhibited higher values than the castrated ones, likely because non-castrated animals were more susceptible to stress. The final pH remained within the range considered optimal for all of the carcasses studied. No differences were observed in the shear force among the breeds or between the two sexes. When appropriately managed, zebu breeds are capable of producing tender meat, thus meeting the demands of the consumer market.

The objective of this study was to evaluate the postweaning history of heifers kept on marandu grass pastures with three canopy heights, in a continuous-grazing system, during the rainy period, on feedlot- or pasture finishing. The effects of three canopy heights (15, 25 and 35 cm) associated with two supplements (mineral salt and protein-energy supplement) and two finishing systems in the dry period (feedlot and open pasture) were studied in the postweaning period during the rainy season. The adopted design was completely randomized, with seven replications (animals) in a 2 × 2 factorial arrangement. The animals which received protein-energy supplement reached the finishing period with greater body weight in relation to those fed mineral salt. In both feedlot and pasture finishing systems, compensatory gain effect was observed in the animals that remained on the low pastures during postweaning compared with the high pastures. This compensatory gain was not verified in the animals that received protein-energy supplement in relation to the mineral salt, and thus the animals were slaughtered beforehand. The heifers on pastures with 25 or 35 cm in height were slaughtered in the same period, and those kept on the low pastures were slaughtered afterwards. The studied factors in the postweaning phase did not affect the carcass characteristics. Animals finished in feedlot slaughtered with the same body weight as those finished on pasture show greater carcass yield, subcutaneous fat deposition and renal pelvic and inguinal fat and greater losses with trimmings for cleaning the main hindquarter meat cuts; however, they provide cuts with the same weight but greater fat cover.

The objective of this study was to evaluate animal performance and carcass characteristics of 64 Nellore young bulls at 22 months of age finished in a feedlot and slaughtered at five body weights (350; 455; 485; 555 and 580 kg) fed diets containing coated or uncoated urea. The experimental design adopted was completely randomized, set in a 4 × 2 factorial arrangement, and for the variables assessed in the control animals, it was 5 × 2. No effect of interaction between slaughter weights and diets were observed, so the variables were analyzed separately, compared by polynomial contrasts and by the F test, respectively. The time animals remained in the feedlot to reach slaughter weights was 66, 88, 145 and 194 days. Average daily gain (ADG) showed quadratic behavior, with a maximum of 1.44 kg/day with animals of 491.7 kg. Dry matter intake (DMI) (kg/day) was similar in all the treatments, but it decreased linearly as body weight increased. The bionutritional efficiency worsened linearly as body weight rose. The elevation in slaughter weight resulted in linear decrease in the percentage of beef round and increase in forequarter. Backfat thickness and rib eye area of the longissimus increased linearly and the percentages of muscle and protein in the carcass reduced and those of fat and ether extract increased linearly as body weight increased. Average daily gain, DMI, feed efficiency and carcass characteristics were not affected by diets containing coated or uncoated urea. However, animals fed coated urea presenter better crude fiber and neutral detergent fiber intake.

Objetivou-se com este trabalho avaliar o desempenho de bovinos de corte em confinamento alimentados com rações contendo silagem de milho ou de cana-de-açúcar, e com diferentes formulações. Foram avaliadas cinco rações: SMF - ração contendo silagem de milho, com formulação fixa durante o período de confinamento; SMV - ração contendo silagem de milho, com formulação variável conforme a fase de confinamento; SCF: ração contendo silagem de cana-de-açúcar, com formulação fixa; SCV: ração contendo silagem de cana-de-açúcar, com formulação variável; SCV/SMV: SCV na metade inicial do confinamento e SMV na metade final. O delineamento experimental foi o inteiramente casualizado, com cinco tratamentos e três repetições (baias). Foram utilizados 285 bovinos castrados, com idade de 36 meses e peso vivo inicial de 362,4 kg. As rações contendo silagem de milho promoveram maior consumo de matéria seca (10,5 kg e 2,4% PV) em comparação àquelas contendo silagem de cana-de-açúcar (10,1 kg e 2,3% PV). Não houve efeito das silagens sobre o ganho médio diário (1,348 kg/animal/dia) e peso vivo ao abate (481,2 kg PV). A ração SCV/SMV promoveu a pior conversão alimentar (8,0 kg MS/kg PV). Os animais alimentados com as rações compostas com silagem de milho apresentaram maior peso de carcaça quente, rendimento de carcaça e espessura de gordura subcutânea (262,1 kg, 54,1% e 6,2 mm) em relação àqueles que receberam a silagem de cana-de-açúcar (252,5 kg, 52,7% e 4,8 mm). A utilização de silagem de cana-de-açúcar em rações para bovinos de corte em terminação é viável e o ajuste da formulação durante o período de confinamento não influencia o desempenho dos animais. A troca de silagem de cana-de-açúcar por silagem de milho durante o período de alimentação interfere negativamente na conversão alimentar.

The objective of the present study was to evaluate the performance of beef cattle in feedlots fed diets containing either whole-crop maize silage or sugarcane silage, and with different formulations. Five diets were evaluated: MSF - diet containing whole-crop maize silage, with fixed formulation during feedlot period; MSV- diet containing whole-crop maize silage, with variable formulation according to feedlot phase; SCSF - diet containing sugarcane silage with fixed formulation; SCSV- diet containing sugarcane silage, with variable formulation; SCSV/MSV- SCSV diet in initial half of fedlot and MSV diet in final half of feedlot period, respectively. It was used a complete random experimental design, with five treatments and three replicates (pens). It was used 285 steers at 36 months of age, with an initial body weight of 362.4 kg. Diets with whole-crop maize silage promoted greater intake of dry matter (10.5 kg and 2.4% BW) compared with diets containing sugarcane silage (10.1 kg and 2.3% BW). There was no effect of the silages on average daily gain (1.348 kg/animal/day) and live weight at slaughter (481.2 kg BW). SCSV/MSV diet promoted the worst feed conversion (8.0 kg DM/kg BW). Animals fed diets composed of whole-crop maize silage presented greater weight of hot carcass, of carcass yield and subcutaneous fat thickness (262.1 kg, 54.1% and 6.2 mm) compared with the animals fed sugarcane silage (252.5 kg, 52.7% and 4.8 mm). The use of sugarcane silage in diets for finishing beef cattle is feasible and the adjustment of formulation during confinement period does not influence performance of the animals. Replacement of sugarcane silage by whole-crop maize silage during the feeding period affects negatively feed conversion.

Objetivou-se avaliar a eficiência bionutricional de tourinhos mestiços F1 Red Angus × Nelore (½ RA ½ N) e F1 Blonde D'Aquitane × Nelore (½ BA ½ N) terminados em confinamento e abatidos com 480, 520 e 560 kg de peso corporal. O delineamento experimental foi inteiramente casualizado em arranjo fatorial 2 × 3 (grupo genético × peso de abate) com seis repetições. Os tourinhos ½ BA ½ N tiveram maior gordura renal, pélvica e inguinal (GRPI, kg e % PV); e menor índice nutricional multivariado biológico (INMB) e consumo alimentar residual em comparação aos tourinhos ½ RA ½ N. Os tourinhos abatidos com maior peso apresentaram maior área de olho-de-lombo (cm²), espessura de gordura subcutânea, gordura de cobertura na garupa, GRPI (kg e % PV), consumo de matéria seca (CMS, kg/d), consumo de energia líquida (MJ/d) e proteína metabolizável (g/dia), e INMB em relação aos abatidos mais leves. Além disso, os tourinhos ½ BA ½ N abatidos com 480 kg tiveram a menor conversão alimentar. Por outro lado, o ganho médio diário de peso (kg/dia), o consumo de matéria seca (% PV e g/UTM), a eficiência alimentar e a relação de Kleiber não diferiram entre os grupos genéticos, os pesos de abate e a interação grupo genético versus peso de abate. Tourinhos F1 Blonde D'Aquitaine × Nelore e os animais abatidos mais leves são bionutricionalmente mais eficientes na fase de terminação em confinamento.

The objective of this study was to assess the bionutritional efficiency of crossbred F1 Red Angus × Nellore (½ RA ½ N) and F1 Blonde D'Aquitaine × Nellore (½ BA ½ N) young bulls finished on feedlot and slaughtered at 480, 520 and 560 kg body weight. A completely randomized experimental design in a 2 × 3 (genetic group × slaughter weight) factorial arrangement with six replicates was used. The ½ BA ½ N young bulls showed higher kidney, pelvic and inguinal fat (KPIF, kg and % BW) and lower multivariate biological nutritional index (MBNI) and residual feed intake than ½ RA ½ N young bulls. The young bulls slaughtered at heavier weight had larger ribeye area (cm²), fat thickness over the 12-13th rib, fat thickness over the rump, KPIF (kg and % BW), dry matter intake (DMI, kg/d), net energy intake (MJ/d) and metabolizable protein intake (g/d), and MBNI compared to young bulls slaughtered at lighter weight. Furthermore, the ½ BA ½ N young bulls slaughtered at 480 kg had lower feed conversion than the others. On the other hand, the average daily weight gain (kg/d), DMI (% BW and g/BW0.75), feed efficiency and Kleiber ratio did not differ between genetic group, slaughter weight and genetic group versus slaughter weight interaction. Therefore, crossbred F1 Blonde D'Aquitaine × Nellore young bulls and animals slaughtered at lighter weights are more bionutritionally efficient in the finishing phase on feedlot.

Objetivou-se avaliar o efeito da inclusão da amônia anidra ou ureia em fenos de resíduo pós-colheita de sementes de Brachiaria brizantha e da fonte proteica suplementar ao feno não-tratado sobre o desempenho e as características de carcaça de bovinos confinados. Vinte e quatro animais não-castrados (12 animais F1 Nelore Aberdeen Angus, variedade preta, e 12 F1 Nelore Aberdeen Angus, variedade vermelha) foram distribuídos aleatoriamente em quatro tratamentos, totalizando seis repetições, considerando blocos o cruzamento e o peso inicial. As dietas experimentais consistiram de feno não-tratado suplementado com nitrogênio não-proteico; feno não-tratado suplementado com farelo de algodão; feno tratado com 5% de ureia; e feno tratado com 3% de amônia anidra (% MS). Os valores de peso vivo inicial, consumo diário e consumo relativo de MS não diferiram entre as dietas e apresentaram médias de 422,6 kg, 9,80 kg e 2,1%, respectivamente. O ganho médio diário (GMD) e a conversão alimentar apresentaram diferenças que evidenciaram melhor desempenho dos animais alimentados com o feno tratado com amônia, cujos valores foram de 1,336 kg/dia e 7,78 kg de MS ingerida/kg de GMD, seguidos daqueles alimentados com o feno não-tratado e suplementado com farelo de algodão, de 1,161 kg/dia e 8,98 kg de MS ingerida/kg de GMD, respectivamente. Os consumos de nutrientes diferiram, resultando em maiores consumos de fibra em detergente neutro (FDN), fibra em detergente ácido (FDA) e celulose pelos animais alimentados com feno tratado com amônia. Os maiores valores de espessura de gordura subcutânea foram obtidos com a dieta com feno tratado com amônia (6,3 mm).

This trial was conducted aiming to evaluate the effects of Brachiaria brizantha vegetative seed harvest residues hay treated with anhydrous ammonia (NH3) or urea, and protein sources on the steers performance, and carcass quality. Twenty-four male beef cattle were (12 F1 Nellore X Aberdeen Angus and 12 F1 Nellore X Red Angus), distributed in four treatments, with six replications. Animal crossbreed type and initial body weight were considered blocks. The diets were: Untreated hay supplemented with non-protein nitrogen (UHNPN); untreated hay supplemented with cottonseed meal (UHCM), hay treated with 5% urea (HTU), hay treated with 3% anhydrous ammonia (HTA) of DM%. Diets were formulated to be isoproteic and isoenergetic. The initial body weight (kg), daily DM intake (kg), and percentage of body weight (% BW) did not differ among treatments, and the average values observed were 422.6 kg, 10.24 kg, and 2.16% BW, respectively. Animals fed with HTA showed better daily weight gain, feed efficiency, 1.336 kg/day, and 7.78 kg/kg of weight gain, followed by the UHCM, 1.161 kg/day, and 8.98 kg/kg, respectively. Animals of the HTA showed highest NDF, ADF and cellulose intake. Carcass fat thickness was highest on the HTA animals, 6.3 mm.

Objetivou-se verificar a economicidade da fase de terminação em confinamento de tourinhos mestiços F1 Red Angus × Nelore (½ RA ½ N) e F1 Blonde D'Aquitaine × Nelore (½ BA ½ N) abatidos com 480, 520 e 560 kg de peso corporal. Trinta e seis bovinos mestiços F1, tourinhos, com 20 meses de idade média inicial: 18 ½ RA ½ N e 18 ½ BA ½ N foram distribuídos a um delineamento experimental inteiramente casualizado em arranjo fatorial 2 × 3 (grupos genético × peso de abate), com seis repetições. Os tourinhos ½ BA ½ N abatidos com 480 kg apresentaram maior ganho de carcaça (kg/dia), eficiência alimentar, valor de produção (R$/dia), saldo de alimentação (R$/dia), custo de nivelamento da dieta (@/t MS) e relação benefício:custo. O rendimento de carcaça dos tourinhos ½ BA ½ N foi maior que o dos tourinhos ½ RA ½ N. À medida que se elevou o peso de abate, o rendimento de carcaça, a conversão alimentar, o custo de alimentação (R$/@ e R$/dia) e o ponto de nivelamento da dieta (kg/dia) aumentaram; ao passo que o saldo de alimentação (R$/@) diminuiu. O índice nutricional multivariado bioeconômico indicou melhor associação com a rentabilidade da fase de terminação de bovinos em confinamento. A análise de sensibilidade não influenciou os resultados obtidos. O benefício foi menor que o custo de alimentação se considerada a relação de troca a partir de 4 @/t MS da dieta. Tourinhos mestiços F1 Blonde D'Aquitaine × Nelore abatidos com 480 kg de peso corporal apresentam melhor eficiência bioeconômica.

The objective in this work was to evaluate the economicity of the finishing phase on feedlot of F1 Red Angus × Nellore (½ RA ½ N) and Blond D'Aquitaine × Nellore (½ BA ½ N) crossbred young bulls slaughtered at 480, 520 and 560 kg of body weight. Thirty-six F1 crossbred young bull with 20 months of initial average age: 18 ½RA½ N and 18 ½N½ BA were allotted to a completely randomized design in a 2 × 3 factorial arrangement (genetic group × slaughter weight), with six replicates. The ½ BA ½ N young bulls slaughtered at 480 kg had the highest carcass gain (kg/day), feed efficiency, gross income (R$/day), gross profit of feed (R$/day), break-even cost of the diet (@/t DM) and cost:benefit ratio. The ½ BA ½ N young bulls also had higher dressing percentage than ½ RA ½ N young bulls. As the slaughter weight rised the dressing percentage, feed:gain ratio, feed cost (R$/@ and R$/day) and break-even point (kg/day) increased; while the gross feed profit (R$/@) decreased. The bioeconomic multivariate nutritional index had better association with the profitability of the finishing phase of beef cattle on feedlot. Sensitivity analysis did not influence the results obtained. The benefit was lower than the feed cost from exchange relation of four (4) @/t DM of the diet. F1 Blond D'Aquitaine × Nellore crossbred young bulls slaughtered at 480 kg of body weight showed the best bioeconomic efficiency.